1) Field of the Invention
The present invention relates to a computer program, a network layer link apparatus, and a network layer link method that use different transmission standards.
2) Description of the Related Art
FIG. 40 is a block diagram of a system configuration of a conventional hierarchical network. A first transmitter 101 and a first transmitter 102 transmit packets at a link L500 based on a first transmission standard (for example, a prescription concerning a local area network (LAN) that is standardized by the IEEE802 committee).
A first element management system (EMS) 201 directly manages the first transmitter 101 concerning a restart, and a setting and a cancellation of a link. A first EMS 202 also directly manages the first transmitter 102 concerning a restart, and a setting and a cancellation of a link, like the first EMS 201.
A first NMS 30 is a host system of the first EMS 201 and the first EMS 202. The network manager operates the first NMS 30. The first NMS 30 makes the first EMS 201 and the first EMS 202 execute the management of the first transmitter 101 and the first transmitter 102, based on a command from the network manager.
The first transmitter 101, the first transmitter 102, the first EMS 201, the first EMS 202, and the first NMS 30 belong to a first layer.
On the other hand, a second transmitter 401 and a second transmitter 402 are used when the first transmitter 101 and the first transmitter 102 are geographically separated far from each other and when these transmitters use a packet. The second transmitter 401 and the second transmitter 402 are provided between the first transmitter 101 and the first transmitter 102.
The second transmitter 401 and the second transmitter 402 provide a path (i.e., a path P400 in FIG. 40) that passes through a plurality of node using a second transmission standard (for example, a synchronous optical network (SONET)). The first transmitter 101 and the first transmitter 102 utilize the path P400 provided by the second transmitter 401 and the second transmitter 402 as one virtual physical link (i.e., a link L500 in FIG. 4).
The first transmitter 101, the second transmitter 401, the second transmitter 402, and the first transmitter 102 are connected via a physical network 70.
A second EMS 501 directly manages the second transmitter 401 the second transmitter 402 concerning a restart, and a setting and a cancellation of a path. A second NMS 60 is a host system of the second EMS 501. The network manager operates this second NMS 60. The second NMS 60 makes the second EMS 501 manage the second transmitter 401 and the second transmitter 402, based on a command from the network manager.
The second transmitter 401, the second transmitter 402, the second EMS 501, and the second NMS 60 belong to a second layer. As the first layer and the second layer are not mutually linked, these layers are operated independently.
As explained above, conventionally, the first layer at the first NMS 30 side corresponding to the first transmission standard is not linked with the second layer at the second NMS 60 side corresponding to the second transmission standard. Therefore, the load of the network manage is large.
Consequently, the network manager is forced to carry out a complex operation. The network manager must investigate about a cross relationship between the link and the path. Then, the network manager must set the path at the second NMS 60 after setting the link at the first NMS 30, based on the understanding about specifications of the first transmitter 101 and the first transmitter 102 and specifications of the second transmitter 401 and the second transmitter 402.
Japanese Patent Application Laid-open Nos. 2002-33767, 2001-36587, and Japanese Patent Application Laid-open No. 2002-84280 disclose related art.